Today marked the end of classes for me (at least for now). I still have a presentation to give tomorrow and a final exam next Monday, but other than that, I’m free! I’m quite happy to be nearing the end of this phase, and am anxious to get to research. So much of my time has been taken up with TA work and course work that I haven’t been very productive on the research front, although I have managed to finish my MS thesis on Cygnus A.
I still have a few things left to wrap up the semester, mostly related to the observing class for which I am a TA.. grading and computing the final grades. That should be all wrapped up by early next week.
Despite the end of courses, the next week and a half should be quite busy… I have to finish a data reduction/calibration of some of the recently acquired GBT data. Additionally, I still have my 45 minute thesis defense to finish up (and the associated edits for the thesis). After that… vacation!
Last night was the Fan Mountain Observatory Public Night. It started out with some clouds on the horizon, which made target selection difficult. However, about halfway through the night, the clouds cleared out and we were treated with a gorgeous view of the sky. All told, we had about 350 visitors!
I spent half the night talking about the Fan Mountain Observatory Bench Optical Spectrograph (FOBOS), which is the workhorse instrument of the 40″ telescope at Fan Mountain. Most of the talk was explaining what a spectrograph is and how astronomers use them to determine the composition and line-of-sight motion of stars. There was one every 20 minutes or so, so we kept pretty busy. And it’s always nice to see people excited about science.
Both the 40″ and 31″ telescopes had eyepieces on them, giving people and opportunity to look through a large telescope! The view through them is always gorgeous. The Charlottesville Astronomical Society was also on hand with many more telescopes, looking at a variety of objects.
My grandparents were up for the public night and had a good time looking through the variety of telescopes. It was great to see them, even if it was only for a short while.
The semester is starting to wrap up here. As usual, that means things are quite busy. The past few days have been spent working on the final project for our “Interstellar Medium” class. David and I are working on a phenomenon called continuum pumping, which can affect the measured spectrum from a gaseous nebula or active galactic nuclei. The basic idea is that the broad continuum from a star can serve to excite atoms, resulting in increased line emission from hydrogen and some metals.
Our final project can be split into basically two parts… the first is to write down the various equations to describe this phenomenon, make simplifying assumptions and compute the additional line emission when continuum pumping is included. The second part is to use a numerical computer code to simulate a gaseous nebula. I have been primarily working on the first part, and am (hopefully) close to a solution. David has been working on the simulations, using Cloudy to get more accurate values. All in all an interesting project. It is fun pretending to be a theorist 
Pictures from the recent New River Gorge climbing trip have been uploaded to flickr Here are a few of my favorites:
For the whole set of pictures see: New River Gorge Climbing on flickr
As I’ve noted before, I am finishing up a M.S. in Imaging Science from RIT. My research has focused on the infrared emission in the powerful radio galaxy Cygnus A. I’m happy to announce that my thesis is ready for the defense! I will be traveling up to Rochester during the second week of May, and giving my ~45 minute defense and working on a paper to publish the results.
Title and abstract:
Modeling the Infrared Emission from Cygnus A
The Spitzer Space Telescope provides a unique view of the Universe at infrared wavelengths. Improved sensitivity and angular resolution over previous missions enable detailed studies of astrophysical objects, both in imaging and spectroscopic modes. Spitzer observations of active galactic nuclei can help shed light on the physical conditions of the central regions of these active glalaxies.
The nearby radio galaxy Cygnus A is one of the most luminous radio sources in the local Universe. In addition to the high radio power, it is also very luminous in the infrared. Spitzer spectroscopy and photometry of Cygnus A is combined with data from the literature at radio and sub-mm wavelengths and modeled with a combination of: a synchrotron emitting jet, a burst of star formation, and emission from an AGN. The infrared emission in Cyngus A shows contributions from all three processes and the models are able to reproduce the observed emission over almost 5 dex in frequency. Evidence is seen for a break in the synchrotron spectrum in the mid-infrared. The relevant component of the infrared emission suggests Cygnus A has a star formation rate of ~20 M_sun per year. Even in the absence of the AGN, it would still be a luminous infrared source.
Three weeks to go! I’ll post updates as they come…
It’s been a rainy day here in Charlottesville. Although I escaped it while climbing this past weekend, it caught up with me. Fortunately (?) I was inside most of the day and didn’t have to contend with the torrential downpour, save during my trip to and from the gym.
The morning was spent grading labs for the 100 level Intro to Observing class. Most of the labs utilized a computer program (CLEA) to “measure” the Hubble Constant. However, one lab involved a significantly larger investment of time. Namely, nightly observations of a Cepheid variable to determine the period over which the brightness changes, and hence its intrinsic luminosity. He did fairly well, observing the star over almost 2 months, getting quite close to the known period.
The semester is wrapping up (only 8 days of classes left!), so I expected to be flooded with labs. Combined with my thesis defense and finishing up my own coursework, it should be a busy next few weeks!
I just got back from the New River Gorge. Aleya and I met Mike and several other folks from Ohio on Friday night. After a bit of a noisy night (me snoring and a goat-guarding-dog continuously barking), we woke up around 8:30, made breakfast and headed towards Beauty Mountain. On the way we stopped at the upper end of “Endless” and warmed up at the “Guide’s Area”. I led Guide’s Left again, and was happy to find I was much more comfortable on it than i was the last time I’d done it. Improvement!
After the warmup, we headed over to “The Brain” at Beauty Mountain. Finding the climbs we were interested in to be already taken, we relaxed a bit and ate lunch. In a short while, the parties moved on and we climbed “Brain Teasers”, “Brain Tweezers”, and “You Want it, You Got it”. I gave the last one a go on lead, falling twice above the 3rd bolt.. It was a fun climb.. something to work on when I come back.
We capped off the day by climbing up The Pinnacle to watch the Sunset… rapping off as the light faded, we called it a night and headed into town for “Pies and Pints”
Today dawned slowly… without a plan, we woke at our own pace. With rain moving in, we opted to relax in town. A bit of hanging out at the gear store and watching the “Earth Day” events pretty much summed it up. We headed back to town early, which gave me ample time to put gear away, and (hopefully soon) get to bed on time!
Newly edited and uploaded pictures from observing in Green Bank have been uploaded to flickr. The Green Bank pictures are included with pictures from a trip in the fall.
Most of today has been spent researching and writing a 10 minute talk for my Extragalactic Astronomy class. I picked “Interacting Galaxies” for my talk.. quite a broad subject. After working a bit and doing some research, I settled on the sub-topic of “feeding the nuclear regions”. Basically, how one gets gas from the outer portions of a galaxy, down to a region comparable to the size of the solar system! Conservation of angular momentum makes this quite difficult!
To give away the punch line, there are known mechanisms for getting the gas down to ~100 parsec (pc), and from getting the gas from ~1 pc into the black hole. Getting the gas from 100 pc to 1pc turns out to be difficult! There are some ideas (supernovae, magnetic fields?, etc), but no obvious method.
Putting observational constraints on this also turns out to be difficult. Most active galactic nuclei lie at such large distances that current telescopes are unable to resolve this crucial region. So the mechanism must be inferred from other observations. Large datasets like the Sloan Digital Sky Survey, which have data on many quasars and other AGN, will hopefully shed some light on the issue.
I had a pretty varied Easter yesterday… did a little bit of everything. I dusted off my road bike and did a 21 mile ride with Andre through the rolling hills South of Charlottesville. It was a nice ride, certainly doable, but a bit of a workout. After that we had a BBQ at my place and watched the 2009 Paris-Roubaix. It was a good race, unfortunately lacking a sprint finish in the velodrome in Roubaix. The evening was rounded out grading and a movie with Aleya. All in all a fairly relaxing weekend.
Today has been fairly uneventful.. After staying up late finishing the grading, I slept in. When I checked my email I was greeted with a mini-flood of emails from students asking about labs. Must be a deadline today 
The afternoon has class as usual. I must admit, I’m very much looking forward to the summer so I can focus on research for the next few years!
But now, time to get some homework done for tomorrow…
